1. Field of the Invention
The invention relates to a process for producing a cohesive, self-adhesive bandage, which does not adhere to the skin, hair and articles of clothing and which is rigid or elastic for fixing, compression and support dressings and permanent elastic compression and support dressings for medical purposes and a bandage produced by this process.
2. Description of the Prior Art
Dressing materials are known as compression and support dressings which, in order to obtain a self-adhering action, are coated on both sides with a contact adhesive in such a way that the adhesive, which is mainly formed from rubber, not only adheres to the outside of the warp and weft threads of the web, but also penetrates deeply into the porous fabric and fiber groups. Even the spaces or pores between the individual warp and weft threads are filled, so that it is no longer really a dressing material, but a rubber strip or band which contains an elastic reinforcing fabric to increase its tearing resistance in the warp and weft. In the case of such dressing materials, it is not possible to refer to individual adhesives particles because the rubber fills the entire volume of the pores, reducing or eliminating the porosity of the fabric, sealing the surface on either side like a film.
Due to the pronounced adhered state of the elastic warp threads in such bandages, the extensibility is greatly reduced, so that it is no longer possible to speak of a plastic behavior of such a bandage when applied to parts of the body with a very small radius. Furthermore, such bandages can only be stretched by about 30 to 40%. As a result of this construction, there is no breathing activity of the fibers, i.e., the bridge formation between skin and external air is lost. In addition, such an impregnation by an adhesive greatly influences the air permeability, water vapor permeability, and secretion absorptivity/water holding capacity, so that undesired heat and moisture chambers are formed which constitute an ideal medium for bacterial and fungal attacks to the skin. Furthermore, the extensibility is greatly reduced by the pronounced adhesion of the elastic elements, because the latter are very seriously negatively influenced in their elastic behavior due to the penetration of the adhesive into the fiber groups and through the covering or casing.
A reusable, elastic compression bandage for medical purposes is known and described in DE-AS No. 1,491,205. This bandage is in the form of an elongated support band made from an at least longitudinally extensible elastic material, the support band being partially coated on either side with a cohesive substance which adheres to itself but not to the skin or articles of clothing The cohesive substance is applied over the entire length of the support band onto those parts of the threads contained therewith which project from the fabric surface, while leaving substantially free the fabric gaps, so that the permeability for air and moisture is ensured. An elastic compression bandage constructed in this way is reusable and rests with a constant pressure on all sides on the body surface. Despite the elastic stress, there is no reduction in the pressure due to sliding of the individual turns of the bandage, particularly in the transverse direction, even when the part of the body carrying the bandage moves. This bandage is also intended to permit prolonged uninterrupted wear, i.e., it has good permeability for air and water vapor and, in particular, it does not adhere to the skin, hair or articles of clothing.
Whereas the adhesive coating can be applied to bandages by the dipping process, in the case of the bandage according to DE-AS No. 1,491,205, the adhesive coating is applied by rollers. In this process, rubber is removed from two spaced parallel tanks and transferred to two further rollers through which the bandage is then guided tangentially upwards. Following a fine adjustment, the two upper rollers uniformly apply the rubber to the bandage moved past. However, it is not possible to achieve such a fine adjustment which permits the coating in a uniform manner of both sides of the bandage. Depending on the density of the fabric, as a function of a more or less stretched state on being fed in, many portions of the bandage are not coated by the two rollers or are only coated on one side, so that portions, or even a complete side of the bandage remains without adhesive, whereas in certain areas of the bandage impregnation has taken place deep down into the said bandage. Therefore, the roller application process does not give a bandage having a uniform distribution of the rubber on both sides.
U.S. Pat. No. 3,364,063 to Satas describes a pressure-sensitive adhesive tape wherein the carrier material is a non-woven fabric and the adhesive substance is an adhesive polymer. The adhesive polymer is applied as a coating on the fibers of the non-woven fabric. Accordingly, the adhesive substance is an adhesive which adheres to skin and hair. FIG. 3 of this patent shows an almost completely closed adhesive, i.e., non-porous layer. This means that a self-adhesive tape has been provided, wherein the adhesive is applied, for example, by a spraying method. In order to obtain sufficient adhesiveness, it is necessary to place adhesive particles very densely on the surface, which has the result that the permeability to air and water is substantially reduced, i.e., the porosity of the fabric is reduced. In U.S. Pat. No. 3,364,063, a self-adhesive tape is produced which does not have any breathing activity of the fibers because the adhesive layer which is applied over the surface of the bandage material extends over the entire surface of the bandage material so that all threads of the fabric, i.e., the warp threads as well as the weft threads, firmly adhere to one another. The adhesive film closes the surface of the bandage fabric. In addition, the adhesive is applied under pressure to the surface of the bandage fabric so that there is no longer any air permeability of the bandage material. By applying the adhesive under pressure, the adhesive penetrates into the interior of the fiber groups and encloses the threads in such a way that the bandages produced are very negatively influenced in their elastic behavior.
U.S. Pat. No. 3,523,528 to Patience discloses spray-deposited discrete spots of, e.g., tacky rubbery material, latex, or resin on fabric substrates. The fabric is a woven, ribbon-like bandage having a low weight per surface area with ravel-resistant side edges, containing elastomeric warp yarns synthetic crimp stretch warp yarns and spun warp yarns (inelastic), wherein spun threads are wound or spun around, for example, the elastomeric warp yarns, so that a differentiated stretchability of the elastomeric warp yarns is achieved. In principle, these are bandages which for three decades have been used as compression bandages in different sequences between rigid and elastic warp threads. In order to obtain a differentiated stretchability of the entire bandage, it is necessary that the elastic threads always have material spun or wound around it, so that the elastomeric threads are limited in their elastic behavior.
When a bandage of this type is used, it loses its compressive power during wearing due to slackening. However, this is true in any elastic bandage because internal friction causes fatigue during wearing and the compression is thereby reduced. In other words, the energy, once expended, is not recovered in the form of compression, i.e., the efficiency must be lower than 100%. This fact is true in all bandage materials known to the experts and represents a "basic axiom of physics" because every material, even if it is razor blade steel, is subjected to fatigue when it is moved because of internal friction and plastic changes. The claims are also exclusively directed to the reduction of the compressive force during wearing of said bandages. This patent merely creates an elastic fabric which is provided with an adhesive layer, wherein this adhesive layer is applied on one side to the surface of the bandage material. It does not describe how the individual adhesive particles are applied to the surface of the bandage fabric or what type of elastic bandage is to be produced.
U.S. Pat. No. 3,577,516 to Gould, et al describes a "wound dressing" which is formed by spraying a hydrophilic, water insoluble polymer. This reference does not describe a porous textile fabric structure having a cohesive design, such as a self-adhesive bandage, but rather, a bandage which is prepared from a spray can. After being sprayed onto the surface of the skin, the polymer which is not water-soluble forms a film. This film is only permeable to air. The spray-on bandage is supposed to protect the wound from bacteria and from contamination from the air.